GB1581767A

GB1581767A - Isoxazolylmethylthiol carbamates and their use as herbicides

Info

Publication number: GB1581767A
Application number: GB30429/77A
Authority: GB
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1976-07-28
Filing date: 1977-07-20
Publication date: 1980-12-17
Also published as: FR2359833B1; IL52365A0; BE857260A; IE45532B1; CH629080A5; DK145717B; CA1108133A; DE2633790A1; AU511197B2; IL52365A; AU2633377A; DK338577A; AT355862B; ZA774535B; DK145717C; PL102149B1; ATA543077A; PL199854A1; FR2359833A1; IT1079363B

Abstract

Novel isoxazolylmethyl thiocarbamates of the formula I are used for controlling undesired plant growth either by themselves or together with a carrier. The symbols in formula I have the meaning given in Patent Claim 1. <IMAGE>

Description

(54) ISOXAZOLYLMETHYLTHIOL CARBAMATES AND THEIR USE AS HERBICIDES (71) We, BASF AKTIENGESELLSCHAFT, a German Joint Stock Company of 6700 Ludwigshafen, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to new and valuable isoxazolylmethylthiol carbamates, herbicides containing these compounds, and methods of controlling the growth of unwanted plants with these compounds.

It is known from French Patent Specification 2,205,514 that the thiolcarbamic acid esters of imidazole have a herbicidal action. However, there is no disclosure of the type of herbicidal activity, e.g., selectivity in and tolerance by crop plants, and application rates. The herbicidal action of the active ingredients is only slight.

Numerous thiol carbamates are known as herbicides. Some of them have achieved considerable importance in agriculture and horticulture for controlling the growth of unwanted plants. A characteristic common to these compounds is the good action on unwanted grasses. However, this action varies from species to species of this family. For instance, N,N-dipropylthiolethyl carbamate controls wild oats (German Published Application DAS 1,031,571), but this species is not listed in the manufacturer's recommendations for N,N-dipropylthiolpropyl carbamate (German Published Application DAS 1,031,571). It is reported that N,N-dipropylthiolethyl carbamate has a good action of Setaria spp., whereas the action of N,N-diisopropylthiol-2,3-dichloroallyl carbamate (German Published Application DAS 1,142,464) was inferior here. In addition to controlling unwanted grasses, some compounds of this class also destroy Cyperaceae and some broadleaved weeds. For instance, N,N-dipropylthiolpropyl carbamate has an extremely reliable action on Cyperus spp., whereas N,N-diisopropylthiol-,dichloroallyl carbamate has practically no effect on these species. An essential criterion for the use of these agents is the difference in selectivity from crop plant to crop plant. Thus, N-ethyl-N-cyclohexylthiolethyl carbamate (British Patent Specification 995,316) is used predominantly in Beta beets. The most important crop plant for N,N-diisobutylthiolethyl carbamate (German Published Application DAS 1,031,571) is Indian corn. This difference is particularly surprising in the case of N,N-diisopropylthiol-2,3-dichloroallyl carbamate and N,N-diisopropythiol-2,3,3trichloroallyl carbamate (German Published Application DAS 1,142,464). Both products can be employed without difficulty in broadleaved crops such as beet and rape. For cereals, the manufacturers and distributors only recommend N,N-diisopropylthiol-2,3,3-trichloroallyl carbamate, as it is less aggressive in these crops.

Prior art thiol carbamates have in general a high vapor pressure, as the following list shows: Active ingredient vapor pressure mm Hg at OC N,N-dipropylthiolethyl carbamate 34 x 10-3 25 N,N-diisobutylthiolethyl carbamate 13 x 10-3 25 N,N-dipropylthiolpropyl carbamate 10.4 x 10-3 25 N-ethyl-N-cyclohexylthiolethyl carbamate 6.2 x 10-3 25 N,N-diisopropylthiol-2,3-dichloroallyl carbamate 1.5 x 10-4 25 N,N.diisopropylthiol-2,3,3-trichloroallyl carbamate 1.2 x 10-4 25 hexahydro- 1 H-azepine- 1 -carbamic acid thiolethyl ester 5.6 x 10-3 25 (German Patent Specification 1,300,947) All these compounds have to be incorporated into the soil to prevent loss through evaporation. In the case of the last compound, the submerging of rice paddies probably has the same effect as incorporation.

Although generally speaking the incorporation of herbicides is positive for a number of reasons, this method of application does have considerable disadvantages, e.g., the work burden is increased, and special incorporation equipment has to be acquired. This makes itself felt particularly at farms having a low degree of mechanization. The seedbed is excessively loosened, and as a consequence certain seeds have emergence difficulties in dry weather. In areas where heavy rainfalls occur, this additional soil treatment increases the risk of erosion, particularly on sloping ground. Similarly, loosening of the soil assists wind erosion in arid wind-swept tracts. For these reasons, attempts are made under the abovementioned conditions to move the soil as little as possible during cultivation ("reduced tillage").

There is therefore a demand for active ingredients which offer an alternative to incorporation. In the field of thiol carbamates with their specific properties, such compounds, with the exception of hexahydro-lH-azepine-l-carbamic acid thiolethyl ester and S-(4-chlorobenzyl)-N,N-diethylthiol carbamate - which are used in rice -, have hitherto not been available. Attempts have recently been made in this direction with the manufacture of thiol carbamate sulfoxides.

We have now found that isoxazolylmethylthiol carbamates of the formula

where R' denotes hydrogen, alkyl, alkyl interrupted by oxygen or sulfur (i.e. alkoxyalkyl or alkylmercaptoalkyl), unsubstituted or alkyl-substituted cycloalkyl, aralkyl, or optionally substituted aryl, R2 denotes hydrogen, optionally substituted alkyl, aryl, or halogen, R3 denotes hydrogen or alkyl, R4 denotes hydrogen or alkyl, and R5 and RO are identical or different and each denotes alkyl, alkenyl, unsubstituted or alkyl-substituted cycloalkyl, alkoxyalkyl or haloalkyl, and additionally R5 and Rs together with the nitrogen atom denote an unsubstituted or lower alkyl-substituted heterocyclic ring having up to 10 ring carbon atoms, preferably 4, 5, 6 or 7 ring members, have a strong herbicidal and selective action.

These active ingredients offer, in addition to the wider spectrum of action, a flexibility in the application hitherto unknown in this class of compounds.

The radicals R contained in the isoxazolylmethylthiol carbamates of the formula I have for instance the following meanings: R' = hydrogen; lower alkyl of a maximum of 6 carbon atoms optionally interrupted by O or S, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, 2-pentyl, 3-pentyl, n-hexyl, isopropylmercaptomethyl, methoxymethyl; cycloalkyl of a maximum of 8 carbon atoms optionally substituted by lower alkyl, e.g. cyclopropyl, cyclopentyl, cyclohexyl, cyclo octyl; aralkyl, e.g. benzyl, l-phenylethyl, 2-phenylethyl; and optionally substituted aryl, e.g. phenyl, chlorophenyl, fluorophenyl, dichlorophenyl, trifluoromethylphenyl; R2 = hydrogen; optionally substituted lower alkyl of a maximum of 6 carbon atoms, e.g. methyl ethyl, isopropyl, chloromethyl; aryl, e.g. phenyl; and halogen, e.g. chloro, bromo, iodo; R3 and R4 = hydrogen, and lower alkyl of a maximum of 6 carbon atoms, especially methyl; R5 and R6 = lower alkyl of a maximum of 6 carbon atoms, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, n-penty'l, 2-pentyl, 3-pentyl, n-hexyl; lower alkenyl of a maximum of 4 carbon atoms, e.g. allyl methallyl, but-2 en-1-yl, but-4-en-l-yl; cycloalkyl of a maximum of g carbon atoms optionally substituted by lower alkyl, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 2-methylcyclopentyl; alkoxyalkyl of a maximum of 6 carbon atoms, e.g. 2-methoxyethyl, 2-ethoxyethyl, l-methoxy-2-propyl, 3 methoxypropyl; haloalkyl of a maximum of 4 carbon atoms, e.g. 2 chloroethyl, I-chloro-2-propyl, 3-chloropropyl; R5 and R6 together with the nitrogen atom may also denote a heterocyclic ring of a maximum of 10 carbon atoms, preferably 4-7 ring members, optionally substituted by one or more lower alkyl groups, e.g. azetidine, 2-methylazetidine, 2,4-dimethylazetidine, 2,4,4-trimethylazetidine, pyrrolidine, 2-methylpyrrolidine, 2-ethylpyrrolidine, 2,5-dimethylpyrrolidine, piperidine, 2-methylpiperidine, 2-ethylpiperidine, 2 methyl-5-ethylpiperidine, hexahydroazepine, 2-methylhexahydroazepine, 2,3 dimethylhexahydroazepine, heptamethylenimine, bicyclo-[3,2,2]-3 azanonane, morpholine, 2,6-dimethylmorpholine, 3,5-dimethylmorpholine.

The compounds according to the invention of the formula I may be prepared in accordance with the process A equation below by reaction of an isoxazolyl methyl halide or isoxazolyl methylalkane sulfonate with a salt of a thiol carbamate.

Process A:

In the above formulae R' to R6 have the above mentioned meanings, X denotes halogen or alkane sulfonate and M denotes an alkali metal atom or ammonium optionally substituted by 2 or 3 alkyls. The starting materials of the formula II employed in process A are known or may be prepared by reaction of nitrile oxides with acetylene halides. Examples of such compounds are 5-chlormethyl-3-methylisoxazole, 5-bromomethyl-3-ethylisoxazole, 5-chloromethyl-3-isopropylisoxazole, 5-bromomethyl-3-tert-butylisoxazole, 5-chloromethyl-3,4-dimethylisoxazole, 5-(1'chloroethyl)-3-methylisoxazole, 5-bromomethyl-3-phenylisoxazole, 5-chloro methyl-3-(3 ',4'.dichlorophenyl)-isoxazole, and 5-bromomethyl-3-cyclohexylisoxazole. The compounds 5-chloromethylisoxazole and 5-bromomethyl-3-methyl4-chloro (or 4-bromo)-isoxazole are known from the literature (Kochetkow and coworkers, Chemical Abstracts, 47, 2167, 1953; Khim. Geterotsikl. Soedin., 1974, 602). The corresponding isoxazolyl methylalkane sulfonates may be prepared from prior art isoxazolyl methanols (Gazz. chim. ital., 69, 536, 1939) in conventional manner by reaction with alkanesulfonic acid chlorides in the presence of agents which bind hydrogen chloride, e.g., pyridine. The isoxazolyl methyl halides may for instance be prepared as follows: Specification Al

238 g (parts by weight) of propargyl bromide, 476 g (parts by weight) of phenyl isocyanate and 158 g (parts by weight) of nitroethane are dissolved in 1500 ml of toluene; at ISO to 200C, I ml of triethylamine (to activate the phenyl isocyanate) is added. The temperature is kept at from 150 to 300C for 3 hours, and 1 ml of triethylamine (4 ml in all) is added each hour. The mixture is then stirred for 1 hour at 70 C and then cooled. The precipitate is suction filtered and the residue rinsed with 1 1 of toluene. The combined filtrates are concentrated and the residue is distilled under an oil pump vacuum. At 590 to 610C/0.2 mm Hg, 310 g (~ 88% of theory) of 5-bromomethyl-3-methylisoxazole distils over (nD5: 1.5168).

C5H > BrNO (176) C H N Br Calc.: 34.2 3.4 7.9 45.5 Found: 34.0 3.4 - 8.0 45.4 60 MHz nmr spectrum (CDCl3; # values) 2.3 (3H, s), 4.44 (2H, s), 6.15 (1H, s) 13C nmr spectrum (CDCl3, ppm values relative to TMS): 167.2 (C), 160.1 (C), 104.5 (CH), 18.8 (CH2), 11.3 (CH3).

Specification A2

93.5 g (parts by weight) of acetohydroximoyl chloride (Ber. dtsch. chem. Ges., 40, 1677, 1907) and 90 g (parts by weight) of isobutynyl chloride are stirred in 1500 ml of benzene; at 15 to 200C, 105 g (parts by weight) of triethylamine is added dropwise. The mixture is then stirred for 1 hour at from 200 to 250C and for 1 hour at 700 C. After the mixture has been allowed to cool it is filtered and the filtrate concentrated. The distillate which remains is distilled under an oil pump vacuum.

There is obtained 133 g (92% of theory), b.p. 48 to 50 C/0.05 mm Hg; nD25: 1.4740.

C6H8NOCl (145.5) C H N Cl Calc.: 49.6 5.5 9.7 24.5 Found: 49.5 5.7 10.0 24.0 60 MHz nmr spectrum (CDCl3; # values): 1.78 (d, 3H), 2.3 (s, 3H), 5.05 (9, 1H), 6.09 (s, 1H).

'3C nmr spectrum (CDCl3, ppm values relative to TMS): 171.5 (C), 159.8 (C), 102.5 (CH), 47.4 (CH), 23.3 (CH3), 11.5 (CH3).

Specification A3

119 g (parts by weight) of propargyl bromide, 95 g (parts by weight) of nitropropane and 440 g (parts by weight) of triethylamine are dissolved in 1200 ml of chloroform; at OOC, 155 g (parts by weight) of phosphoroxy chloride is added dropwise. The mixture is kept at 200C for 30 minutes and refluxed for 2 hours.

After the mixture has been cooled, filtration and concentration are carried out, and the residue is taken up in water. The water phase is extracted several times with toluene and the combined toluene phases are washed with water and subsequently dried over sodium sulfate. The sodium sulfate is then separated and the filtrate concentrated; the residue is distilled under an oil pump vacuum. At 78 to 79 C/0.1 mm Hg, 150 g (79% of theory) distil off; nD25: 1.5108.

C H8BrNO (190) C H N Br Calc.: 37.9 4.7 7.4 42.0 Found: 38.0 4.6 7.6 41.7 The following compounds are obtained analogously:

The compounds designated with formula III are salts of thiocarbamic acids.

Typical representatives, which may be prepared in conventional manner, are the sodium salts or the ammonium salts - optionally substituted by 2 or 3 alkyls - of N,N-dimethylthiolcarbamic acid, N,N-diethylthiolcarbamic acid, N,N-diisopropylthiolcarbamic acid, N,N-di-n-propylthiolcarbamic acid, N,N-di-n-butylthiolcarbamic acid, N,N-diisobutylthiolcarbamic acid, N-ethyl-N-n-butylthiolcarbamic acid, N-ethyl-N-isopropylthiolcarbamic acid, N-ethyl-N-cyclohexylthiolcarbamic acid and N,N-diallylthiolcarbamic acid. Also, salts of N-azetidine-, N-pyrrolidine-, N-piperidine- and N-hexahydroazepinethiolcarbamic acid and their derivatives substituted in thering by 1 to 3 methyl and/or ethyl groups, may be used.

Process A may be carried out in the presence of an inert organic solvent, for instance hydrocarbons, e.g. cyclohexane, benzene, toluene; halogenated hydrocarbons, e.g. methylene chloride, chloroform, carbon tetrachloride, chlorobenzene; ethers, e.g. diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, glycol dimethyl ether; lower alcohols and ketones, e.g. methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, cyclohexanone; nitriles, e.g. acetonitrile; and water. Mixtures of these solvents may also be used.

For the preparation of the new active ingredients, process A is preferred.

If desired, however, the isoxazolylmethylthiol carbamates of the formula I according to the invention may be prepared in accordance with process B by reaction of isoxazolylmethyl mercaptans or their salts with carbamic acid chlorides.

Process B

In these formulae, R' to R6 have the above meanings and Y denotes hydrogen, an alkali metal atom, or ammonium optionally substituted by 2 or 3 alkyls.

Formula IV represents starting materials which may be prepared by conventional methods from the isoxazolyl methyl halides of the formula II by reaction with hydrogen sulfide or salts thereof (e.g. Houben-Weyl, Methoden der Organischen Chemie, IX, 1--18). The following are examples of mercaptans of the formula IV: 3-methylisoxazolyl-5-methylmercaptan, 3-ethylisoxazolyl-5-methyl mercaptan, 3-phenylisoxazolyl-5-methylmercaptan, 3-methylisoxazolyl-5-( I ethyl)-mercaptan.

Examples of carbamoyl chlorides of the formula V are those of dimethylamine, dietylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, N-ethyl-nbutylamine, N-ethyl-n-isopropylamine, azetidine, pyrrolidine, piperidine, hexahydroazepine and derivatives thereof substituted on the ring by I to 3 methyl and/or ethyl groups.

Process B is expediently carried out in the presence of a hydrogen chloride acceptor. Suitable for this purpose are inorganic bases, e.g. alkali metal bicarbonates, carbonates and hydroxides; organic bases, such as alkali metal alcoholates, e.g., sodium methylate; tertiary amines, e.g. triethylamine and N,Ndimethylcyclohexylamine; and saturated or unsaturated nitrogen heterocycles, e.g.

N-methylpiperidine, pyridine and quinoline. The process is advantageously carried out using one of the solvents (or mixtures thereof) listed under process A.

Isoxazolylmethylthiol carbamates of the invention of the formula I may also be prepared in accordance with process C by reaction of an isoxazolylmethylthiochlorocarbonic acid ester with a secondary amine.

Process C:

In these formulae, R' to Re have the abovementioned meanings.

The thiochlorocarbonic acid esters of the formula VI may be prepared in conventional manner from the isoxazolylmethylmercaptans of the formula IV (Y=hydrogen) and phosgene. Examples of compounds of the formula VI are 3methylisoxazolyl-5-methylthiocarbonyl chloride, 3-ethylisoxazolyl-5-methylthiocarbonyl chloride, and 3-phenylisoxazolyl-5-methylthiocarbonyl chloride. Suitable secondary amines of the formula VII are particularly those listed at process B as components of the carbamic acid chlorides. Process C may be carried out using the inert solvents mentioned under process A - less advantageously in alcohols or water - and with or without the addition of one of the hydrogen chloride acceptors mentioned under process B.

In detail, process A may for instance be carried out as follows: At from -20" to +50 C, 1 mole of an isoxazolylmethyl halide or alkane sulfonate of the formula II, optionally in one of the above solvents, is dripped into a solution or suspension of at least I mole of a thiol carbamate of the formula III. To complete the reaction, the mixture is stirred for from 3 to 12 hours at from 0 to 80"C. Upon completion of the reaction, the mixture is poured into water and the product is extracted, if desired with an inorganic solvent immiscible with water, and subsequently isolated by distillation or crystallization.

Process B may for instance be carried out in the following manner: A solution of I mole of isoxazolylmethylmercaptan of the formula IV in a solvent is reacted with at least one mole of a carbamic acid chloride of the formula V in the presence of at least I mole of one of the abovementioned inorganic or organic bases at from --100 to +800C and for from I to 12 hours. The thiol carbamate according to the invention of the formula I is isolated as described above.

Process C is for instance carried out as follows: A solution of 1 mole of a thiochlorocarbonic acid ester of the formula IV in an inert organic solvent is reacted with at least 1 mole of an amine or the formula VII; the acid-binding agent may be at least 1 mole of the inorganic or organic bases mentioned in process B. The reaction temperature is from -10" to +80"C and the reaction time from I to 12 hours, as in process B, depending on the reactants, the base and the solvent employed. The thiol carbamate is isolated as described above.

The following examples, in which the parts are by weight, illustrate the processes for preparing the isoxazolylmethylthiol carbamates according to the invention of the formula 1.

EXAMPLE 1.

At 0 C, 60.0 parts of carbonylsulfide was gassed into a mixture of 102 parts of N-ethylcyclohexylamine, 80.8 parts of triethylamine and 700 parts of methylene chloride, and the whole was stirred for 2 hours at room temperature. Subsequently, 105.3 parts of 3-methyl-5-chloromethylisoxazole was dripped in over a period of 1 hour at OOC, and the mixture stirred for 10 hours at room temperature. The salt which had formed was filtered off and the filtrate was washed successively with water, IN hydrochloric acid and again with water, and dried. After removal of the solvent, distillation of the residue gave 194.2 parts of 3-methyl-5-isoxazolylmethyl N-ethyl-N-cyclohexylthiol carbamate, b.p. (0.2 mm Hg) 176--1790C (m.p.

60"--62"C).

EXAMPLE 2.

At OOC, 8.0 parts of carbonyl sulfide was gassed into a mixture of 21.2 parts of diisopropylamine in 100 parts of toluene, and the whole stirred for 30 minutes at 0 C and for 1 hour at room temperature. Subsequently, 19.0 parts of 3-ethyl-5bromomethylisoxazole was dripped in over a period of 15 minutes and the whole stirred for 3 hours at room temperature. After working up as in Example 1, there was obtained 21.8 parts of 3-ethyl-5-isoxazolylmethyl-N,N-diisopropylthiol carbamate having a boiling point at 0.3 mm Hg of 154--156"C (n25: 1.5089).

EXAMPLE 3.

While cooling, 29.8 parts of N,N-diethylcarbamic acid chloride was dripped into a mixture of 25.8 parts of 3-methylisoxazolyl-5-methylmercaptan in 100 parts of ether and 50 parts of pyridine; the whole was then refluxed for 3 hours. After working up as in Example 1, there was obtained 35.8 parts of 3-methyl-5-isoxazolylmethyl-N,N-diethylthiol carbamate having a boiling point at 0.05 mm Hg of 136"--138"C.

EXAMPLES 4-75.

The following isoxazolylmethylthiol carbamates according to the invention may be prepared by one of the abovementioned processes.

Phys. data No. R1 R2 R3 R4 R5 R6 (b.p./mm Hg; m.p.; nD25) 4 CH3 H H H i-C3H7 i-C3H7 143/0.05 (68 C) 5 CH3 H H H - (CH2)6 - nD25 1.5435 6 CH3 H CH3 H C2H5 C2H5 124/0.05 7 CH3 H CH3 H i-C3H7 i-C3H7 132/0.05 8 CH3 H CH3 H - (CH2)6 - 160/0.2 9 CH3 H H H n-C3H7 n-C3H7 139/0.05 2 C2H5 H H H i-C3H7 i-C3H7 Example 2 10 CH3 H H H CH2-CH(CH3)2 CH2-CH(CH3)2 143/0.05 11 CH3 H H H n-C4H9 n-C4H9 164/0.2 12 CH3 H H H CH@-CH=CH2 CH2-CH=CH2 144/0.2 1 CH3 H H H C2H5 cyclo-C6H11 Example 1 13 CH3 H H H C2H5 n-C4H9 147/0.3 14 CH3 H H H - (CH2)5-CH(CH3) - 170/0.4 15 CH3 H H H - (CH2)3 - m.p. 72-73 C 16 CH3 H H H - CH(CH3)-CH2-C(CH3)2 - 148/0.2 17 CH3 H H H - CH(CH3)-CH(CH3)-(CH2)4 - 184/0.4 Phys. data No. R1 R2 R3 R4 R5 R6 (b.p./mm Hg; m.p.; nD25)

u oU o ;I o a l ~ Cl oo A o d H H H i-C3 H7 i-C3 H7 m.p. 99-1()PC ID x n: ac) Ar oo 20 C2H5 H H H C2H5 C2H5 144/0.1 21 C2H5 H H H n-C3H7 n-C3H7 152/0.2 22 C2H5 H H H - (CH2)6 - 180/0.3 23 C2H5 H H H - CH(CH3)-(CH2)5 - 184/0.3 24 C2H5 H H H - CH(CH3)-CH(CH3)-(CH2)4 - 190/0.2 25 C2H5 H H H n-C4H9 n-C4H9 168/0.1 26 C2H5 H H H - CH(CH3)-CH2-C(CH3)2 - 139/0.05 27 C2H5 H H H C2H5 n-C4H9 154/0.1 28 C2H5 H H H - CH(C2H5)-(CH2)4 - 170/0.1 29 C2H5 H H H - CH(CH3)-(CH2)4 - 165/0.2 30 C2H5 H H H - CH(CH3)-(CH2)3 - 166/0.1 31 C2H5 H H H C2H5 cyclo-C6H11 180/0.1 32 CH3 H H H C2H5 i-C3H7 124/0.04 Phys. data No. R1 R2 R3 R4 R5 R6 (b.p./mm Hg; m.p.; nD25) 33 CH3 H H H CH2CH2OCH3 CH2CH2OCH3 200/0.4 34 CH3 H CH3 H - CH(CH3)-CH2-C(CH3)2 - 136/0.01 35 CH3 H CH3 H - CH(CH3)-(CH2)5 - 167/0.01 36 CH3 H CH3 H - CH(CH3)-CH(CH3)-(CH2)4 - 157/0.01 37 CH3 H H H - (CH2)2-O-(CH2)2 - m.p. 74-76 C 38 CH3 H H H CH2-CH(CH3)2 CH-CH2-CH3 152/0.2 # CH3 39 CH3 Cl H H CH(CH3)2 CH(CH3)2 148/0.2 40 CH(CH3)2 H H H CH(CH3)2 CH(CH3)2 148/0.2 41 C2H5 H H H CH2CH=CH2 cyclo-C6H11 187/0.1 42 C2H5 H H H CH(CH3)2 CH2-CH(CH3)2 153/0.1 43 C(CH3)3 H H H CH(CH3)2 CH(CH3)2 144/0.2 44 C(CH3)3 H H H C2H5 cyclo-C6H11 168/0.1 45 C(CH3)3 H H H -CH(CH3)-CH2-C(CH3)2 - 142/0.1 46 C(CH3)3 H H H C2H5 n-C4H9 152/0.1 47 CH3 Cl H H C2H5 cyclo-C6H11 178/0.2 48 CH3 Cl H H C2H5 n-C4H9 157/0.2 Phys. data No. R1 R2 R3 R4 R5 R6 (b.p./mm Hg; m.p.; nD25) 49 CH3 Cl H H - CH(CH3)-CH2-C(CH3)2 - 147/0.2 50 CH3 Cl H H - CH(CH3)-CH(CH3)-(CH2)4 - 180/0.2 51 CH3 H CH3 H n-C3H7 n-C3H7 156/0.1 52 CH3 H CH3 H CH2CH(CH3)2 CH2-CH(CH3)2 157/0.2 53 CH3 H CH3 H CH2-CH=CH2 CH2-CH=CH2 150/0.1 54 CH3 H CH3 H C2H5 n-C4H9 148/0.1 55 CH3 H CH3 H CH(CH3)2 CH2-CH(CH3)2 142/0.1 56 C2H5 H CH3 H CH(CH3)2 CH(CH3)2 148/0.1 57 C2H5 H CH3 H C2H5 cyclo-C6H11 170/0.1 58 C2H5 H CH3 H C2H5 n-C4H9 143/0.1 59 C2H5 H CH3 H CH(CH3)2 CH2-CH(CH3)2 146/0.1 60 C2H5 H CH3 H CH2-CH(CH3)2 CH(CH3)-CH2-CH3 142/0.08 61 CH(CH3)2 H CH3 H C2H5 cyclo-C6H11 184/0.1 62 CH(CH3)2 H CH3 H CH(CH3)2 CH(CH3)2 oil 63 C(CH3)3 H CH3 H CH(CH3)2 CH(CH3)2 90 C

U 0 o :c va 65 CH(CH3)2 H CH3 H C2H5 n-C4H9 164/0.1 Phys. data No. R1 R2 R3 R4 R5 R6 (b.p./mm Hg; m.p.; nD25) 66 C(CH3)3 H CH3 H C2H5 n-C4H9 165/0.2 67 C(CH3)3 H CH3 H C2H5 cyclo-C6H11 73 C 68 C(CH3)3 H CH3 H CH2-CH(CH3)2 CH(CH3)-CH2-CH3 172/0.1 69 CH3 H CH3 H - CH2-CH2-CH2-CH2-CH(CH3) - 76 C 70 CH3 H CH3 H - CH2-CH2-CH2-CH(CH3) - 140/0.01 71 CH3 H CH3 H - CH2-CH2-CH2-CH2-CH(C2H5) - 1.5297 72 C2H5 H CH3 H -CH(CH3)-CH2-C(CH3)2 - 1.5129 73 CH3 H CH3 H - CH2-CH2-CH= CH-CH2 - 46-47 C

No C1 In . .

G3 CR 74 CHa H CH3 H HH3CC4t 1.5258 3 t v: Examples demonstrating the herbicidal action of the new isoxazolylmethyithiol carbamates A series of experiments, divided in the main into the following three groups, was carried out to provide evidence in support of the statements made in the introduction about these active ingredients.

I. Greenhouse experiments The vessels employed were paraffined paper cups having a volume of 200 cm3, and the substrate was a sandy loam containing about 1.5% (wt%) humus. The seeds of the test plants were sown shallow and separated according to species. The active ingredients were applied immediately (preemergence treatment), suspended or emulsified in water as the distribution medium and sprayed onto the soil surface by means of finely distributing nozzles. Prior to the chemical treatment, the cups were lightly sprinkler-irrigated; the agents therefore came into contact with moist soil.

After application of the agents the vessels were covered with transparent plastic hoods until the plants had taken root. This cover prevented the evaporation of water and readily volatile substances. Another effect was the more uniform emergence of the test plants, to the extent that they were not impaired by chemicals. When postemergence treatment was employed, the plants were first grown in the vessels to a height of from 3 to 10 cm, depending on the form of growth, and then treated. A cover was not used. Depending on the temperature requirements of the plants, the experiments were set up either in the cooler (l00-200C) or warmer (180--300C) portion of the greenhouse. The experiments lasted for from 2 to 6 weeks. During this period, the plants were tended and their reaction to the individual treatment was evaluated. The substances examined, the dose rates employed (in kg/ha of active ingredient) and the types of plant used in the experiments are given in the following tables. A 0--100 scale was used for assessment, 0 denoting no damage or normal emergence, and 100 denoting complete destruction or non-emergence.

II. Experiments in the open These experiments were carried out on small plots of various sizes. The soil was a sandy loam having a pH of 56 and 1-1.5% humus. The compounds were applied from early to late fall and from early to late spring, corresponding to the sowing period for the crop plants. The compounds were emulsified or suspended in water as carrier and distribution medium, and applied by means of a motor-driven plot spray mounted on a hitch. The application methods most frequently employed were preplant incorporation and preemergence surface application. In individual experiments, the action of the agents when sprayed during emergence of the crop plants and weeds, and postemergence after formation of a few genuine leaves was examined. All the experiments were run for several months; during this period assessments were made at certain intervals employing the 0 to 100 scale.

III. Herbicidal action via the vapor phase The remarkable herbicidal action of isoxazolylmthylthiol carbamates, even when not incorporated into the soil as is necessary with prior art thiol carbamates, suggested that the losses of active ingredient through evaporation were low. To examine this, the following exp

Results The individual results from the various experiments and tables combine to give the following picture.

1) The introduction of the isoxazolylmethyl radical into the thiol carbamates resulted in a shift in action, particularly in a broadening of the range of action compared with prior art thiol carbamates. Thus, for instance, some compounds developed an activity embracing that of N,N-diisopropylthiol-2,3-dichloroallyl carbamate or N,N-diisopropylthiol-2,3,3-trichloroallyl carbamate and of N,N dipropylthiolethyl carbamate (cf. Tables 2, 3 and 5). In other instances, a similar, at times somewhat poorer, herbicidal performance to that N-ethyl-N cyclohexylthiolethyl carbamate was found. However, the selectivity range in crop plants was incomparably greater (cf. Table 6). It should be pointed out at this juncture that the prior art thiol carbamates were only employed in the experiments because of their action as herbicides. Compounds having a structure similar to that of the compounds of the invention are hitherto unknown. A thiol carbamate having a heterocyclic ring and known as a herbicide had insignificant activity (Table 3). The corresponding dithiol carbamate was completely ineffective. Table 4 contains a further example of the herbicidal action of the new isoxazolylmethylthiol carbamates.

2) Whereas prior art thiol carbamates can only be used in specific crop plants or groups thereof (e.g., broadleaved species) because of (a) their phytotoxicity, (b), incorporation necessary for herbicidal action, and (c) the weed spectrum combatted, some of the new compounds have an improved and wider selectivity (Tables 3, 5, 6 and 7). Plant physiology may provide an explanation for the selectivity of the compounds of the invention; the selectivity may also be attributable in part to the application method employed. Immobile substances distributed on the surface of the soil do not come into contact in phytotoxic amounts with the seeds and roots of the crop plants lying somewhat deeper. This selectivity is apparent in the case of compounds which can be left on the surface of the soil after application, but does not exist when the active ingredients have to be incorporated into the soil because of their high vapor pressure or for other reasons, in order to avoid evaporation losses.

3) The new compound according to the invention had, when incorporated before sowing, an action similar to that of prior art compounds. When applied without incorporation they were superior to the prior art thiol carbamates suitable for the crop in question (Table 8). Remarkable in this connection is the fact that for instance the compound 3-methyl-5-isoxazolylmethyl-N,N-diisopropylthiol carbamate, when applied preemergence to the surface, combatted unwanted plants in Indian corn just as well as significant prior art preemergence herbicides of different structure (Table 9). Successful control was also obtained during and after emergence of the unwanted plants; the crop plants remained unaffected (Tables 8, 10).

4) The phytotoxicity of the vapors of N,N-diisopropylthiol-2,3,3-trichloroallyl carbamate for wild oats is known. This was confirmed in model experiments. Of the new compounds, it was found that for instance the substance 3-methyl-S- isoxazolylmethyl-N,N-diisopropylthiol carbamate had just as aggressive an action on the crop plant oats in the directly treated vessels as N,N-diisopropylthiol-2,3 dichloroallyl carbamate or N,N-diisopropylthiol-2,3,3-trichloroallyl carbamate.

The plants in the untreated pots located in the same glass cylinder remained undamaged by this new compound, whereas plant growth in the case of the comparative compound has suffered (Table 11). Consequently, not enough active ingredient has escaped from the directly treated pots to cause damage, via the gas phase, to the neighboring test plants. The actual vapor pressure of 3 methyl-5-isoxazolylmethyl-N,N-diisopropylthiol carbamate was 1.3 x 10-5 mbar at 20"C, whereas that of N,N-diisopropylthiol-2,3-dichloroallyl carbamate at the same temperature was 3.7 x 10-4 mbar.

It goes without saying that the experimental results discussed here are only examples of the reaction of numerous unwanted and crop plants from a wide variety of botanical families. The application rates too can be varied beyond the examples; they depend on the end to which they are applied and on local conditions (site, plant size), and may for instance vary from 0.1 to 10 kg of active ingredient per hectare.

The particular advantage of this new group of isoxazolylmethylthiol carbamates over prior art thiol carbamates is the range of possible application methods.

TABLE 1 List of the plants used in the experiments Latin name Abbreviation in tables English term Alopecurus myosuroides Alopec. myosur. slender foxtail Amaranthus retroflexus Amar. retro. pigweed Avena fatua Avena fat. wild oat Beta vulgaris Beta vulg. sugarbeet Brassica napus rape Chenopodium album lambsquarter Cynodon dactylon Cynod. dactyl. Bermudagrass Cyperus esculentus Cyper. escul. yellow nutsedge Echinochloa grus galli Echin. e.g. barnyardgrass Eleusine indica Eleus. ind. goosegrass Euphorbia geniculata Euph. genic. South American member of the spurge family Glycine max soybeans Gossypium hirsutum Gossyp. hirs. cotton Hordeum vulgare barley Lolium multiflorum Lolium multifl. Italian ryegrass Matricaria spp. Matric. spp. chamomile Poa annua annual bluegrass Setaria faberii Set. fab. giant foxtail Setaria spp. foxtail spp.

Solanum nigrum black nightshade Sorghum halepense Sorgh. halep. johnsongrass Stellaria media chickweed Triticum aestivum Tritic. aest. wheat Zea mays Indian corn TABLE 2 Action on important weed grasses in the greenhouse; preemergence treatment Basic molecule

Substituents in the Compound Application Test plants and % damage substances examined no. rate Alopecurus Avena Echinochloa kg/ha myosuroides fatua crus galli R1 R2 R3 6 0,75 60 - 80 1,5 90 - 90 3,0 100 - 90 3 0,75 95 0 60 1,5 100 80 70 3,0 100 80 75 4 0,75 90 65 85 1,5 95 95 90 3,0 95 100 95

I I o RAZZ I C2115 C112-,-Cl prior art 1,9 95 I 95 o 95 90 99 o H n sd h O h ! ffi n i 0,75 40 80 0 C3H7n C3H7n C2H5 prior art 1,5 90 90 20 3,0 95 95 70 TABLE 2 (Continued) Action on important weed grasses in the greenhouse; preemergence treatment Test plants and % damage Compound Application rate Alopec. Avena Echinochloa No. kg/ha myosur. fatua crus galli 34 2.0 94 98 94 39 2.0 95 92 80 4.0 100 100 78 40 1.0 80 95 90 2.0 90 95 95 23 2.0 80 80 90 4.0 100 100 95 24 2.0 90 60 85 4.0 100 100 90 0 = no damage. 100 = complete destruction.

Test plants and % damage Substituents in Com- Appl. the substances Brassica Glycine Gossy. Zea Alopec. Amar. Cyperus Echin. Eleus. Euph. Poa Setaria Solanum Sorgh. Stellaria pound rate examined napus max hirs. mays myosur. retro. escul. c.g. ind. genic. annua spp. nigrum halep. media R1 R2 R3 no. kg/ha

c(C cH( -C?-N02 PaftO 1.0 0 20 - 0 0 0 - - - 0 0 - 0 - 0 4.0 0 90 - 25 90 20 - - - 10 80 - 10 - 0 l oo H le o l OG 18 ll 11 4 G 0 l o ooX 0n ll No ooa 00 00 H p, h SZOl g fo ~cu oJ r 02 U 1,0 0 0 10 0 100 100 42 90 100 100 100 90 90 82 20 4 2,0 0 5 20 10 100 100 85 95 100 100 100 100 90 95 30 4,0 0 15 27 10 100 100 85 95 100 100 100 100 100 97 60 1,0 0 0 0 0 100 100 60 95 100 60 100 100 100 72 0 2 2,0 0 5 0 0 100 100 60 95 100 95 100 100 100 95 30 4,0 0 15 5 - 100 100 82 95 100 95 100 100 100 95 70 1,0 0 0 20 0 80 100 30 57 85 60 70 0 70 45 10 9 2,0 0 0 25 0 100 100 55 92 100 60 100 15 70 75 80 4,0 0 5 45 0 100 100 55 95 100 90 100 40 100 90 80 1,0 0 0 0 0 60 100 10 55 22 50 0 30 90 15 70 10 2,0 0 0 0 0 70 100 32 80 85 50 0 45 90 20 80 4,0 0 5 15 0 100 100 32 80 95 95 0 65 100 50 80 1,0 0 0 0 0 60 100 10 20 52 20 80 0 90 15 0 13 2,0 0 0 10 20 80 100 40 85 95 20 90 0 90 45 0 4,0 0 0 12 20 80 100 70 95 100 70 90 55 100 67 0 1,0 0 10 0 0 0 90 - 60 50 - 90 10 25 10 0 27 2,0 0 10 0 0 10 95 - 95 90 - 100 80 60 60 0 4,0 0 10 10 10 90 100 - 95 90 - 100 85 90 70 0 1,0 0 0 0 0 90 0 - - - 90 40 0 90 - 0 7 2,0 0 0 0 0 90 0 - - - 90 90 - 90 - 0 4,0 0 0 0 20 - 90 - - - 90 100 - 100 - 0 1,0 0 0 0 0 60 95 - 60 80 30 90 20 30 10 0 20 2,0 0 0 0 0 100 - - 90 95 30 100 75 30 65 0 4,0 0 0 20 10 100 95 - 95 95 70 100 95 70 95 0 1,0 0 0 0 0 90 90 - 85 90 100 100 55 70 60 0 21 2,0 0 0 10 0 100 95 - 95 95 100 100 85 80 60 0 4,0 0 10 20 0 100 100 - 95 100 100 100 95 100 70 0 Table 3 Substituents in Test plants and % damage the substances Com- Appl. examined pound rate Brassica Glycine Gossyp. Zea Alopec. Amar. Cyperus Echin. Eleus. Euph. Poa Setaria Solanum Sorgh. Stellaria napus max hirs. mays myosur. retro. escul. c.g. ind. genic. annua spp. nigrum halep. media R1 R2 R3 no. kg/ha 14 1,0 0 0 5 0 100 90 20 80 85 30 90 40 90 45 0 2.0 0 0 12 10 100 90 50 95 97 70 100 95 90 85 0 4.0 0 0 12 10 100 100 77 97 100 100 100 100 80 90 0 1.0 0 0 10 0 60 100 15 85 85 90 100 35 100 47 100 17 2,0 0 0 17 0 100 100 30 95 100 100 100 65 100 92 100 4,0 0 5 32 0 100 100 42 97 100 100 100 100 100 92 100 1.0 0 0 0 0 90 90 35 55 60 45 80 5 30 15 0 5 2.0 0 0 2 0 90 90 40 92 97 45 90 20 30 40 0 4.0 0 5 5 40 100 100 50 95 100 80 100 60 90 55 60

ooo I I I I I I I 9"88 1 o, 1 1 N N N 92 ! 100 - 40 80 92 - 30 100 - 50 20 art 4.0 0 - 92 C 100 , 65 92 92 - 90 100 - 70 20 t~0 N i O CS CZ I OOU I O illl O O Q cN N | Z l l l ll 000 1 O O O ~ N t oh h h j i j oN C4H9n C2H5 C2H7n " 1.0 - 5 0 0 - 30 - 20 60 20 - 20 0 30 2.0 - 5 10 0 - 70 - 60 90 20 - 60 0 70 4.0 - 25 20 10 - 95 - 70 90 90 - 80 30 90 C3H7@ C3H7@ Cl Cl " 1.0 0 0 5 0 100 40 0 15 92 80 100 90 50 67 0 2.0 0 15 17 0 100 40 10 75 95 80 100 95 80 85 0 CH2-C = CH 4.0 0 35 22 15 100 90 40 87 100 80 100 100 80 90 0 C@H7n C3H7n C2H5 " 1.0 0 5 5 0 70 20 55 50 72 30 90 65 0 40 40 2.0 0 5 10 0 90 20 75 50 95 30 90 95 0 57 40 4.0 0 25 15 20 100 100 75 60 95 100 100 100 30 70 50

: ooo : 80 I ooo I mr ss uo F o 888 ooo o o 888 cz o o j 85 1 58 co c: 8 I oo I E:O, ' 888 C. H, r, 1.0 0 0 0 10 100 95 30 80 100 90 100 80 50 90 0 012 Cl 2.0 N 0 7 20 100 95 40 95 100 90 100 100 70 90 0 4.0 0 10 7 20 100 100 40 95 '100 100 100 100 90 95 0 i ! ooo O O O O O O ~ CU 7 li U li U 0 = no damage 100 = complete destruction TABLE 4 Herbicidal action of new isoxazolylalkylthiol carbamates in the greenhouse; pre- and postemergence application Test plants and % damage Compound Appl. rate Cyperus Echinochloa Lolium No. kg/ha Method escul. crus galli multifl.

26 3.0 PRE - 90 90 3.0 POST 90 90 90 28 3.0 PRE - 90 70 3.0 POST 90 90 90 29 3.0 PRE - 90 90 3.0 POST 70 90 50 33 3.0 PRE - 0 0 3.0 POST 0 90 50 38 3.0 PRE - 90 30 3.0 POST 90 90 90 PRE - preemergence treatment.

POST = postemergence treatment.

0 - no damage.

100 - complete destruction.

TABLE 5 Selective control of grassy weeds in beet with various thiol carbamates in the open; preplant incorporation Basic molecule

Substituents in the Test plants and % damage compounds examined Compound Appl. rate Beta Alpecurus R1 R2 R3 No. kg/ha vulgaris myosuroides 2 2.0 5 95 16 2.0 0 75 3 2.0 5 80 10 4.0 0 65 13 4.0 0 50 9 4.0 50 70 14 4.0 50 90

C3H7i C3H7i Cl Cl 2.0 0 30 II CH2-C = C-Cl 4.0 0 80 prior art c3H7n C3H7n C2H5 prior art 2.0 10 80 4.0 30 95 0 = no damage.

100 = complete destruction.

Table 6 - Herbicidal action and crop plant tolerance in the greenhouse; preemergence application Basic molecule

Substituents in Compound Appl. Test plants and % damage the compounds no. rate examined kg/ha Beta Brassica Gossyp. Tritic. Am@r. Cynod. Echin. Setaria Solanum Sorghum vulg. napus hirs. ae@tivum retr. dactyl. c.g. spp. nigrum halepense R1 R2 R3 1 2,0 0 0 5 0 90 75 87 50 95 70 4,0 0 0 10 0 100 95 92 65 95 75

i co g 88 1 2 i 00 i rm sr O O 00 1 eu Z 4 j sd O h uo u 31 2,0 0 0 0 0 95 - 95 85 80 60 4,0 0 0 10 10 100 - 95 90 90 60 0 = no damage 100 = complete destruction Table 7 - Tolerance of some thiol carbamates by rape and spring wheat in the open; preplant incorporation Basic molecule

Substituents in the Compound Appl.rate Test plants and % damage compounds examined no. kg/ha Brassica Triticum Alopecurus napus aestivum+ myosuroides++ R1 R2 R3 4 2,0 0 0 82 4,0 0 5 95 C3H7i C3H7i Cl Cl prior art 2,0 0 - 86 CH2-C = CH 4,0 0 - 100 C3H7i C3H7i Cl Cl prior art 2,0 0 2 58 4,0 0 8 92 CH2-C = C-Cl C4H9i C4H9i C2H5 prior art 1,5 0 15 30 3,0 0 82 75 C3H7n C3H7n C2H5 prior art 1,5 0 12 25 3,0 10 88 82 0 = no damage 100 = complete destruction + = spring wheat ++ = grassy weed as an indicator of the herbicidal action TABLE 8 Action of some thiol carbamates when applied by different methods in cereals in the open.

Basic molecule

Substituents in the Compound App.rate Appl. Test plants and % damage compounds examined no. kg/ha method Hordeum Tritic. Alopec. Matric. vulgare aest. myosur. spp.

R1 R2 R3 1) 2) 3) 2,0 I 2,5 0 68 9 4 2,0 II 0 1,2 85 54 2,0 III 0 0 93 65 2,0 IV 0 - 72 20 C3H7i C3H7i Cl Cl 2,0 I 0 2,5 70 6 prior art 2,0 II 0 0 51 23 CH2-C = C 2,0 III 0 0 42 20 Cl 2,0 IV - - 65 5

0 O mo rc\\o Ct LnCh LnU3LLn i OOLn( Im 2 H H H H , c2c prior art 2,0 II 0 0 64 30 2,0 III 0 5 65 65 0000 | FI N N N i h o l iF i | l I LS oN I C > l to I O 1) I = Preplant incorporation II = Preemergence III = Application to emerging plants IV = Postemergence 2) winter barley 3) winter.wheat 0 = no damage 100 = complete destruction TABLE 9 Action of 3-methyl-5-isoxazolylmethyl-N,N-diisopropylthiol carbamate applied preemergence in the open without incorporation; comparison with prior art compounds Compound Appl.rate Test plants and % damage Zea mays Echinochlca Chenopodium crus galli album

I t I I N-C1,-S-CH20 4.0 0 95 60 CR1 3 7 (Active I 0 0 I no. tD rU\D (U I \O P ti t' tt I 85 35 : C'H 24:0o 49 '5 CH7i prior art o /CH2 -0-CR3 - o 65 20 a: a 95 70 ti prior art tt | ffi t 55 62 I I I t 4.0 t t 75 I I prior art OO 3 1 OO l O O l O O < ." I I O U t O I I | O N I N Ou I N | I = I n X ts t U t X I j U I O t z UE t l' t I I I I o W NtoN | = 4 0 = no damage 100 = complete destruction TABLE 10 Herbicidal action and crop plant tolerance of some thiol carbamates in the greenhouse; postemergence treatment.

Basic molecule

R1 R2 R3 Compound App.rate Test plants and % damage no. kg/ha Beta Gossyp. Alop. Avena Cyper. Echin. Eleus. Set. vulg. hirs. myo. fat. escul. c.g. indic. fab.

4 1,0 0 0 80 75 65 78 20 55 2,0 0 0 90 88 65 78 60 70 C3H7i C3H7i Cl Cl 1,0 0 - 50 70 - - - prior art 2,0 0 - 90 70 - - - CH2-C = CH

I LTL I LTLf\ I 0 I LC3 1 =r J 1 00 C2115 C2H5 . 1,0 - 0 - 2C) 10 L(5 10 55 CR2-' NCl prior art2,0 - 5 - 60 30 50 59 i o CO h h o h O ,J cJ II O 3S t un cD 0 = no damage 100 = complete destruction TABLE 11 Phytotoxicity of the vapor phase of some thiol carbamates to the crop plant oats Basic molecule

Compound Appl. rate Green weight of Avena sativa in g R1 R2 R3 No. kg/ha directly treated in parallel vessel C3H7i C3H7i Cl Cl 1,0 1,3 CDE 2,7 FG 2,0 0,6 ABC 1,9 EF CH2-C = CH 4,0 0,2 AB 1,1 BCDE

OCIW LUCI I WCI I LpU WUF9 C5H7i C3H7i Cl Cl 1,0 1,8 DEF 2,7 FG 2,0 1,0 BCDE 1,5 CDE CH2-C = C 4,0 0,82 ABCD 1,7 DEF 000 vvv ~ 11 I vy V c I v v 1,0 1,5 CDE 3,7 H 4 2,0 0,8 ABCD 3,6 GH 4,0 0,2 AB 3,5 GH Control (untreated) - 3,7 H Values having a letter in common are not significantly different (Duncan's new multiple range test, level 0.05) 22. Steel, R.G.D. and Torrie, J.H. - Principles and Procedures of Statistics, New York, Toronto, London 1960, pp. 481.

TABLE 12 Selective herbicidal action in rice; preemergence application in the greenhouse Test plants and % damage Compound Oryza Echinochloa Cynodon Setaria No. kg/ha sativa crus galli dactylon app.

34 0,5 13 79 75 71 1,0 19 86 95 92 0 = no damage.

100 = nonemergence or complete withering.

In view of the methods of application possible with the compounds of the invention, they, or compositions containing them, may be used not only in the crops listed in the tables but also in a wide variety of other crops for combatting unwanted plant growth. Application rates may be from 0.1 to 15 kg/ha and more, depending on the object to be combatted. Individual crop plants are listed below: Botanical name English name Allium cepa onions Ananas comosus pineapple Arachis hypogaea peanuts (groundnuts) Asparagus officinalis asparagus Avena sativa oats Beta vulgaris spp. altissima sugarbeets Beta vulgaris spp. rapa fodder beets Beta vulgaris spp. esculenta table beets, red beets Brassica napus var. napus rape Brassica napus var. napobrassica Brassica napus var. rapa turnips Brassica rapa var. silvestris Camellia sinensis tea plants Carthamus tinctorius safflower Citrus limon lemons Citrus maxima grdpefruit Citrus reticulata Citrus sinensis orange trees Coffea arabica (Coffea canaphora, Coffea liberica) coffee plants Cucumis melo melons Cucumis sativus cucumber Cynodon dactylon Bermudagrass in turf and lawns Daucus carota carrots Elaeis guineensis oil palms Fragaria vesca strawberries Glycine mad soybeans Botanical name English name Gossypium hirsutum (Gossypium arboreum Gossypium herbeceum Gossypium vitifolium) cotton Helianthus annuus sunflowers Helianthus tuberosus Hevea brasiliensis rubber plants Hordeum vulgare barley Humulus lupulus hops Ipomoea batatas sweet potatoes Lactuca sativa lettuce Lens culinaris lentils Linum usitatissimum flax Lycopersicon lycopersicum tomatoes Malus spp. apple tree Manihot esculenta cassava Medicago sativa alfalfa (lucerne) Mentha piperita peppermint Musa spp. banana plants Nicotiana tabacum (N. rustica) tobacco Olea europaea olive trees Panicum miliaceum Phaseolus lunatus limabeans Phaseolus mungo mungbeans Phaseolus vulgaris snapbeans, green beans, dry beans Pennisetum glacum Petroselinum crispum spp. tuberosum parsley Picea abies Norway spruce Abies alba fir Pinus spp. pine trees Pisum sativum English peas Prunus avium cherry trees Prunus domestica plum trees Botanical name English name Prunus persica peach trees Pyrus communis pear trees Ribes sylvestre redcurrants Ribes uva-crispa Ricinus communis Saccharum officinarum sugar cane Secale cereale rye Sesamum indicum Sesami Solanum tuberosum Irish potatoes Sorghum bicolor (s. vulgare) grain sorghum Sorghum dochna Spinacia oleracea spinach Theobroma cacao cacao plants Trifolium pratense red clover Triticum aestivum wheat Vaccinium corymbosum blueberries Vaccinium vitis-idaea cranberries Vicia faba tick beans Vigna sinensis (V. unguiculata) cow peas Vitis vinifera grapes Zea mays Indian corn, sweet corn, maize The new isoxazolylalkylthiol carbamates of the invention may be mixed with numerous representatives of other groups of herbicidal active ingredients. Such combinations broaden the spectrum of action and have in some cases synergistic effects. The following compounds are examples of those which can be mixed with the compounds of the invention:

isopropy 1 , 3 -CH-C:CH.

CH3 , 3 I, C2H5 C2H5 -CH2-0CH3 2H5 C H C2H5 -CH,-C-OC,H call5 SH3 cHa00J CH3 CH2-CH2-OCll3 CH3 CH2=CH-CH2- CH2=CH-CH2

R R1 R2 CH H ~(3~ H CH3 CH3 H3CO H CH3 C1 H H CH3 F3C H3C H CH3 C1 CH, ci- H C'H3c=cH ci-o- H CH3 CH3 CH3 H M -N OH3 CH3 H F30 Br-t H OCh3 C1 H OCH3

R 1 R 2 R C1- OCH3 acJ H OCH C1 H3Co- 9- H H3CO- H OCI{3 C1

ol R2 R R1 tert. C4H9 TH2 SUCH3 AH3 tert. C4H9 -N=CH-CH SCH3 \CH3 NH2 CH3

R R1 R2 R3 R4 H CF3 H n.C3H7 n.C3H7 H CF3 H n.C3H7 CH2CH2C1 H SO2NH2 H n.C3H7 n.C3H7

H CF3 H 7 CH2 /C2I15 H3 CH3 H H C2H5 C2H5 H CF3 NH2 n.C3H7 n.C3H7

R R1 X tert.C4H9 C2H5 SCH3 i.C3H7 C2H5 Cl

3 7 C1 .37 C2H5 C2H5 C1 0113 C H -C-ON C1 CH3

R Cu 4 -C- cs Cl -C-CN C1 C2H5 --CH2-o-CH3 C1 3 R 3 ŏN.Y'D I t 3C 3 anion R '11 CH3

Br NC < OH and salts Br and and salts T Br 02Nt10-N=CHoOH and salts N02 Br

and salts

and salts and salts and salts

OR C ,H 7n.

H CI HO 0 and salts C-OCH 3 o R - H or Na COOCH 3 C1 eC1 COOOI{3 COOII { < C1 and salts C1 N112 Cl- CH2 C OH and salts or esters C1 C1 Cl- > -O-CH2-C-OH and salts or esters 0 C1

Cl-9"O-(CH2)3-C-OH and salts or esters / te C1 n . .

C" =H,-O- -NHCil L (1 3 HO w As-ONa HO O OH3 Cl4OeO-CH-C-O-Na I 1 0 C1 COOR F3C -N02 0 k N-C-CH2-0-S-NH i-propyl o o 0 CN-C-CH2-0-S-NH i-propy 1 It is also useful to be able to apply the new compounds according to the invention, either alone or in combination with other herbicides, in admixture with other crop protection agents, e.g., agents for combatting pests and phytpathogenic fungi, and growth regulators. The new compounds may also be mixed with mineral fertilizer solutions used to overcome nutritional or trace element deficiencies.

Application may be effected for instance in the form of directly sprayable solutions, homogenized in water by means of wetting or dispersing agents, adherents or emulsifiers. Concentrates which are suitable for dilution with water may be prepared from active ingredient, wetting agent, adherent, emulsifying or dispersing agent and possibly solvent or oil.

Examples of surfactants are: alkali metal, alkaline earth metal and ammonium salts of ligninsulfonic acid, naphthalenesulfonic acids, phenolsulfonic acids, alkylaryl sulfonates, alkyl sulfates, and alkyl sulfonates, alkali metal and alkaline earth metal salts of dibutylnaphthalenesulfonic acid, lauryl ether sulfate, fatty alcohol sulfates, alkali metal and alkaline earth metal salts of fatty acids, salts of sulfated hexadecanols, heptadecanols, and octadecanols, salts of sulfated fatty alcohol glycol ethers, condensation products of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensation products of naphthalene or naphthalene or naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ethers, ethoxylated isooctylphenol, ethoxylated octylphenol and ethoxylated nonylphenol, alkylphenol polyglycol ethers, tributylphenol polyglycol ethers, alkylaryl polyester alcohols, isotridecyl alcohols, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers, ethoxylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters, lignin, sulfite waste liquors and methyl cellulose.

Powders, dusts and broadcasting agents may be prepared by mixing or grinding the active ingredients with a solid carrier.

Granules, e.g. coated, impregnated or homogeneous granules, may be prepared by bonding the active ingredients to solid carriers. Examples of solid carriers are mineral earths such as silicic acid, silica gels, silicates, talc, kaolin, Attaclay, limestone, lime, chalk, bole, loess, clay, dolomite, diatmoaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground plastics, fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, and ureas, and vegetable products such as grain flours, bark meal, wood meal, and nutshell meal and cellulosic powders.

The formulations generally contain from 0.1 to 95, and preferably 0.5 to 90, % by weight of active ingredient.

There may be added to the compositions or individual active ingredients (if desired, immediately before use (tank-mix)) oils of various types, wetting agents or adherents, herbicides, fungicides, nematocides, insecticides, bactericides, trace elements, fertilizers, antifoams (e.g., silicones), growth regulators, antidotes and other herbicidally effective compounds. The last-mentioned herbicidal compounds may also be applied before or after the individual active ingredients according to the invention or compositions thereof.

These agents may be added to the herbicides according to the invention in a ratio by weight of from 1:10 to 10:1. The same applies to oils, wetting agents and adherents, fungicides, nematocides, insecticides, bactericides, antidotes and growth regulators.

EXAMPLE 76.

90 parts by weight of compound I is mixed with 10 parts by weight of Nmethyl-a-pyrrolidone. A mixture is obtained which is suitable for application in the form of very fine drops.

EXAMPLE 77.

20 parts by weight of compound 2 is dissolved in a mixture consisting of 80 parts by weight of xylene, 10 parts by weight of the adduct of 8 to 10 moles of ethylene oxide to 1 mole of oleic acid-N-monoethanolamide, 5 parts by weight of the calcium salt of dodecylbenzenesulfonic acid, and 5 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

EXAMPLE 78.

20 parts by weight of compound 3 is dissolved in a mixture consisting of 40 parts by weight of cyclohexanone, 30 parts by weight of isobutanol, 20 parts by weight of the adduct of 7 moles of ethylene oxide to 1 mole of isooctylphenol, and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

EXAMPLE 79.

20 parts by weight of compound 4 is dissolved in a mixture consisting of 25 parts by weight of cyclohexanol, 65 parts by weight of a mineral oil fraction having a boiling point between 210 and 280"C, and 10 parts by weight of the adduct of 40 moles of ethylene oxide to 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

EXAMPLE 80.

20 parts by weight of cornpound > 4 is well mixed with 3 parts by weight of the sodium salt of diisobutylnaphthalene-o-sulfonic acid, 17 parts by weight of the sodium salt of a ligninsulfonic acid obtained from a sulfite waste liquor, and 60 parts by weight of powdered silica gel, and triturated in a hammer mill. By uniformly distributing the mixture in 20,000 parts by weight of water, a spray liquid is obtained containing 0.1% by weight of the active ingredient.

EXAMPLE 81.

3 parts by weight of compound 4 is intimately mixed with 97 parts by weight of particulare kaolin. A dust is obtained containing 3% by weight of the active ingredient.

EXAMPLE 82.

30 parts by weight of compound 4 is intimately mixed with a mixture consisting of 92 parts by weight of powdered silica gel and 8 parts by weight of paraffin oil which has been sprayed onto the surface of this silica gel. A formulation of the active ingredient is obtained having good adherence.

EXAMPLE 83.

40 parts by weight of compound 5 is intimately mixed with 10 parts of the sodium salt of a phenolsulfonic acid-urea-formaldehyde condensate, 2 parts of silica gel and 48 parts of water. Dilution in 100,000 parts by weight of water gives an aqueous dispersion containing 0.04 wt% of active ingredient.

EXAMPLE 84.

20 parts of compound 6 is intimately mixed with 2 parts of the calcium salt of dodecylbenzenesulfonic acid, 8 parts of a fatty alcohol polyglycol ether, 2 parts of the sodium salt of a phenolsulfonic acid-urea-formaldehyde condensate and 68 parts of a paraffinic mineral oil. A stable oily dispersion is obtained.

Claims

WHAT WE CLAIM IS:

1. An isoxazolylmethylthiol carbamate of the formula

wherein R' denotes hydrogen, alkyl, alkyl interrupted by oxygen or sulfur, unsubstituted or alkyl-substituted cycloalkyl, aralkyl, or optionally substituted aryl, R2 denotes hydrogen, optionally substituted alkyl, aryl, or halogen, R3 denotes hydrogen or alkyl, R4 denotes hydrogen or alkyl, and R5 and R6 are identical or different and each denotes alkyl, alkenyl, unsubstituted or alkyl-substituted cycloalkyl, alkoxyalkyl or haloalkyl, and additionally R6 and R8 together with the linking nitrogen atom may denote an unsubstituted or lower alkyl-substituted heterocyclic ring'having up to 10 ring carbon atoms.

2. An isoxazolylmethythiol carbamate as claimed in claim 1 wherein any alkyl radical has a maximum of6 carbon atoms, and cycloalkyl radical has a maximum of 8 carbon atoms, any aryl radical contains a single benzene ring and any alkenyl radical has a maximum of 4 carbon atoms.

3. An isoxazolylmethylthiol carbamate as claimed in claim 1 wherein R1 denotes alkyl of 1 to 4 carbon atoms or optionally halogen-substituted phenyl, R2 denotes hydrogen or chlorine, R3 denotes hydrogen or methyl, R4 denotes hydrogen, and R5 and R8 independently denote alkyl or alkenyl (other than 1alkenyl) of 2 to 4 carbon atoms, cyclohexyl, or alkoxyalkyl of at least two carbon atoms in the alkyl moiety and å maximum of 6 carbon atoms, or RO and RB together with the linking nitrogen atom denote an unsubstituted or methyl substituted saturated N-heterocyclic ring of 4 to 7 ring members optionally including an oxygen atom in addition to the nitrogen atom.

4. An isoxazolylmethylthiol carbamate identified herein as any of compounds Nos. 1 to 75.

5. 3-Methyl-5-isoxazolylmethyl-N,N-diisopropylthiol carbamate.

6. 3-Methyl-5-isoxazolylmethyl-N-ethyl-N-cyclohexylthiol carbamate.

7. 3-Methyl-5.isoxazolylmethyl-N,N-diethylthiol carbamate.

8. A process for the production of an isoxazolylmethyithiol carbamate claimed in claim 1, wherein an isoxazolyl methyl halide or methyl alkane sulfonate of the formula

wherein R1 to R4 have the above meanings and X denotes halogen or alkane sulfonate, is reacted with a thiol carbamate of the formula

where R5 and R6 have the above meanings and M denotes an alkali metal atom or ammonium optionally substituted by 2 or 3 alkyls.

9. A process for the production of an isoxazolylmethylthiol carbamate as claimed in claim 1, wherein an isoxazolylmethylmercaptan of the formula

where R' to R4 have the above meanings and Y denotes hydrogen, an alkali metal atom or ammonium optionally substituted by 2 or 3 alkyls, is reacted with a carbamic acid chloride of the formula

where R5 and R6 have the above meanings.

10. A process as claimed in claim 8 or 9 carried out substantially as hereinbefore described or illustrated in any of Examples 1 to 3.

11. Isoxazolylmethylthiol carbamates when prepared by a process as claimed in any of claims 8 to 10.

12. The use of an isoxazolylmethylthiol carbamate claimed in any of claims I to 7 or 11 as a herbicide.

13. A herbicidal composition comprising an isoxazolylmethylthiol carbamate claimed in any of claims 1 to 7 or 11 and a solid or liquid carrier.

14. A herbicidal composition as claimed in claim 13 in the form of a wettable powder or a dust or granules.

15. A herbicidal composition as claimed in claim 13, in the form of a solution paste, emulsion concentrate, suspension or dispersion in an oily liquid.

16. A herbicidal composition as claimed in claim 13 in the form of an aqueous suspension or dispersion containing a wetting or dispersing agent, adherent or emulsifier.

17. A herbicidal composition as claimed in any of claims 13 to 16, containing a further biologically active ingredient.

18. A herbicidal composition as claimed in claim 17 wherein the further biologically active ingredient is a herbicide.

19. A herbicidal composition as claimed in claim 18 wherein the further herbicide is one depicted hereinbefore.

20. A herbicidal composition as claimed in claim 13 and substantially as hereinbefore described or exemplified in any of Examples 76 to 84.

21. A process for producing a herbicidal composition wherein an isoxazolylmethylthiol carbamate as claimed in any of claims 1 to 7 or 11 is admixed with a solid or liquid carrier.

22. A process for controlling the growth of unwanted plants wherein a phytotoxic amount of an isoxazolylmethylthiol carbamate as claimed in any of claims 1 to 7 or 11 is applied to the locus where the growth is to be controlled.

23. A process for selectively controlling the growth of weeds in a crop wherein a selectively phytotoxic amount of an isoxazolylmethylthiol carbamate as claimed in any of claims 1 to 7 or 11 is applied to the crop area.

24. A process as claimed in claim 22 or 23 wherein the herbicide is applied preemergence of the unwanted plants or weeds.

25. A process as claimed in any of claims 22 to 25 wherein the herbicide is applied without incorporation into the soil.

26. A process as claimed in any of claims 23 to 25 wherein the crop is rape, cotton, maize, beet, soyabean, barley, wheat or oats.

27. A process as claimed in claim 22 or 23 carried out substantially as hereinbefore described.